Class DarterFish

java.lang.Object
  |
  +--Fish
        |
        +--DarterFish

All Implemented Interfaces:

Locatable

public class DarterFish

extends Fish

AP® Computer Science Marine Biology Simulation:
The DarterFish class represents a fish in the Marine Biology Simulation that darts forward two spaces if it can, moves forward one space if it can't move two, and reverses direction (without moving) if it cannot move forward. It can only "see" an empty location two cells away if the cell in between is empty also. In other words, if both the cell in front of the darter and the cell in front of that cell are empty, the darter fish will move forward two spaces. If only the cell in front of the darter is empty, it will move there. If neither forward cell is empty, the fish will turn around, changing its direction but not its location.

DarterFish objects inherit instance variables and much of their behavior from the Fish class.

The DarterFish class is copyright© 2002 College Entrance Examination Board (www.collegeboard.com).

Version:

1 July 2002

Constructor Summary

DarterFish(Environment env, Location loc)
Constructs a darter fish at the specified location in a given environment.

DarterFish(Environment env, Location loc, Direction dir)
Constructs a darter fish at the specified location and direction in a given environment.

DarterFish(Environment env, Location loc, Direction dir, java.awt.Color col)
Constructs a darter fish of the specified color at the specified location and direction.

Method Summary

protected void	generateChild(Location loc) Creates a new darter fish.
protected void	move() Moves this fish in its environment.
protected Location	nextLocation() Finds this fish's next location.

Methods inherited from class Fish

act, breed, changeDirection, changeLocation, color, die, direction, emptyNeighbors, environment, id, isInEnv, location, randomColor, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DarterFish

public DarterFish(Environment env,
                  Location loc)

Constructs a darter fish at the specified location in a given environment. This darter is colored yellow. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

DarterFish

public DarterFish(Environment env,
                  Location loc,
                  Direction dir)

Constructs a darter fish at the specified location and direction in a given environment. This darter is colored yellow. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

dir - direction the new fish is facing

DarterFish

public DarterFish(Environment env,
                  Location loc,
                  Direction dir,
                  java.awt.Color col)

Constructs a darter fish of the specified color at the specified location and direction. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

dir - direction the new fish is facing

col - color of the new fish

Method Detail

generateChild

protected void generateChild(Location loc)

Creates a new darter fish.

Overrides:

generateChild in class Fish

Parameters:

loc - location of the new fish

move

protected void move()

Moves this fish in its environment. A darter fish darts forward (as specified in nextLocation) if possible, or reverses direction (without moving) if it cannot move forward.

Overrides:

move in class Fish

nextLocation

protected Location nextLocation()

Finds this fish's next location. A darter fish darts forward two spaces if it can, otherwise it tries to move forward one space. A darter fish can only move to empty locations, and it can only move two spaces forward if the intervening space is empty. If the darter fish cannot move forward, nextLocation returns the fish's current location.

Overrides:

nextLocation in class Fish

Returns:

the next location for this fish